1. Field of the Invention
The present invention relates to a laminate having a mono-crystal oxide conductive member on a silicon substrate, an actuator using such a laminate, an ink jet head used in an ink jet recording apparatus, and a method for manufacturing such an ink jet head.
2. Related Background Art
In recent years, printers using an ink jet recording apparatus as a printing device for a personal computer and the like have widely been popularized because they have good printing performance and are easy to handle and are inexpensive. There are various types of ink jet recording apparatuses such as an ink jet recording apparatus of type in which a bubble is generated in ink by thermal energy and an ink droplet is discharged by a pressure wave caused by the bubble, an ink jet recording apparatus of type in which an ink droplet is sucked and discharged by an electrostatic force, an ink jet recording apparatus of type in which a pressure wave caused by an oscillating element such as a piezoelectric and electrostrictive element is utilized, and the like.
In general, the ink jet recording apparatus utilizing the piezoelectric and electrostrictive elements is constructed to have pressure chambers communicated with an ink supplying chamber and ink discharge ports communicated with the pressure chambers and to include oscillating plates joined to piezoelectric elements disposed within the respective pressure chambers. With this arrangement, by expanding and contracting the piezoelectric element by applying predetermined voltage to the piezoelectric element, flexion oscillation is generated to compress ink in the pressure chamber, thereby discharging an ink droplet from the ink discharge port. Nowadays, while color ink jet recording apparatuses have been popularized, enhancement of a printing performance thereof, particularly high resolving power, high speed printing and increase in length of the ink jet head has been sought. To this end, by utilizing a multi nozzle head structure in which the ink jet heads are miniaturized, the high resolving power and the high speed printing have been realized. In order to miniaturize the ink jet head, the piezoelectric element for discharging the ink must be made smaller.
The actuator and the ink jet head, in order to make the piezoelectric and electrostrictive element smaller, it is required that the piezoelectric and electrostrictive element itself be more minute and has high piezoelectric constant not to decrease its driving capacity even if it is miniaturized. This indicates that a film having excellent crystallization of the piezoelectric and electrostrictive film is needed. The film having excellent crystallization means a uni-orientation film oriented in the same direction and a mono-crystal film having surface orientation firmly aligned. Further, in order to make the piezoelectric element and electrostrictive film to mono-crystal, a layer directly underlying the piezoelectric element film must be mono-crystal upon manufacturing the piezoelectric element film and good grating matching between the piezoelectric element film and the direct underlying layer must be maintained.
As a material providing the good grating matching between PZT piezoelectric element film and the direct underlying layer, an element using SRO which is also used as electrode material is constructed, as disclosed in Japanese Patent Application Laid-open No. 6-280023 (1994). However, in the above proposal, SRO is multi-crystal, and there is no description regarding a method for utilizing a piezoelectric element having good orientation property or mono-crystal.
By the way, for example, in order to form the mono-crystal of an oxide conductive member such as SRO on silicon, epitaxial growth is required. However, in order to achieve the epitaxial growth, an expensive method such as an MBE method is required. Further, for example, in Japanese Patent Application Laid-open No. 11-26296 (1999), a method for film-forming a mono-crystal SRO layer on the silicon is disclosed. This method is a method for forming a film via a mono-crystal layer of YSZ and BaTiO3 to provide stress relaxation on the silicon in order to film-form the SRO. In this method, there were problems that crystallization of the SRO firm-formed on the silicon is apt to be worsened since the unnecessary plural layers are used and that good crystallization of the piezoelectric film formed on the SRO is hard to be obtained. Further, if mono-crystal bodies formed by a Bernoulli method are stuck together and polished, a film thickness is limited and a uniform film cannot be obtained, and, since the film itself cannot be used as an oscillating plate, it cannot be used as an electrode of an actuator of a micro-machine, which requires a thin film thickness. Furthermore, if an actuator and an ink jet head using oxide conductive material directly formed on the silicon as the electrode are driven, peeling at an interface between the oxide conductive material and the silicon is apt to occur thereby to worsen endurance.